The field of the present invention is mechanisms for valve actuation in engines.
Decompression devices have been developed which are employed to reduce the forces required to start an engine. Such devices typically reduce the pressure within the combustion chamber during a first compression stroke by maintaining an intake or exhaust valve partially open during that portion of the initial engine cycle. Such an operation enables additional angular momentum to be established in the engine, such that during the successive cycle or cycles the engine is turning over fast enough to complete a second compression cycle and successfully ignite the charge in the combustion chamber.
Typically such decompression devices employ a mechanism separate and apart from the normal valve opening and closing device as a means for retaining the selected valve partially open during compression. One example of such a device having a manual decompression mechanism is disclosed in Japanese Patent Application Publication No. 59-74317 (74317/1984). Another such a device employing a governor is illustrated in Japanese Patent Application No. 61-40715 (40715/1985).